Treating tobacco

ABSTRACT

Tobacco is treated with a compound of the following general formula   IN WHICH R1 -H, -CH3, or -C2H5, and R2 -H, -CH3, or -C2H5. The tobacco smoke is thus aromatized in a controlled manner and an intensified total flavor impression is obtained.

United States Patent [72] Inventors Georg Neurath Hamburg; Michael Dunger, Hamburg; Herbert Wichern, Halstenbek, all of Germany 21 AppLNo. 801,155

[22] Filed Feb. 20, 1969 [45] Patented Oct. 5, 1971 [73] Assignee 11.1". 8: Ph. F. Reemtsma Hamburg, Germany [32] Priority Feb. 23, 1968 [3 3] Germany [54] TREATING TOBACCO 10 Claims, No Drawings [52] U.S. Cl 131/17, 131/ 144 [51 Int. Cl A24b03/l2, A24b 15/04 [50] Field ofSearch 131/17,

[56] References Cited UNITED STATES PATENTS 3,047,433 7/1962 Bavley etal. 131/17 OTHER REFERENCES The Merck Index," (pub.) Eighth Edition 1968, published by the Merck & Co., Rahway, N.J., U.S.A., p. 639 & 640 cited Primary Examiner-Melvin D. Rein Attorney-Wilson & Fraser ABSTRACT: Tobacco is treated with a compound of the following general formula TREATING TOBACCO The present invention relates to methods for influencing the flavor of tobacco smoke and a principal aim of the invention is to make it possible to produce predictable flavoring results. Although the invention is more particularly concerned with natural tobaccos, it can also be applied to synthetic or artificial tobacco foil. The invention can be applied to natural tobaccos lacking in aroma or tobaccos which are neutral in flavor. Furthermore the invention may be applied to substances to be smoked which are not of a tobacco nature, for example medicinal cigarettes or to cigarettes or to cigarette filter materials. For the sake of convenience of terminology in the present specification and claims, and because the invention is chiefly applicable to smoking materials from the tobacco plant, all smoking and filter materials are spoken of as tobacco.

in accordance with German Pat. No. 1,131,580 synthetic tobacco fibers were produced by subjecting a chosen tobacco mixture to alternating extraction treatments to remove watersoluble and alcohol-soluble armoma materials which were then mixed in the form of a dry extract with a carrier substance of cellulose or methylcellulose material. The fibers were spun so as to produce a cigarette tobacco resembling a natural cigarette tobacco mixture.

The aim of this method was exclusively the production of a synthetic tobacco which was free of woody and cellulosic tobacco constituents. There was no intentionto bring about a systematic and predictable flavoring of a given natural tobacco or natural tobacco mixture.

A similar principle was followed in the method described in British Pat. specification 989,703 in which tobacco rich in aroma was subjected to careful extraction, for instance with ice-cold water, the extract so obtained freeze-dried and applied to tobacco which was poor in aroma. This method can be used for extracting one or more components of a tobacco and adding it to another tobacco, both tobaccos later being used for producing a cigarette tobacco mixture. The method could be used for adding the flavor of a tobacco to a tobacco mixture without the necessity of adding the tobacco itself, that is to say only its extract would be added.

Further methods of making extracts from natural tobaccos are described in the British Pat. specification 298,151. In accordance with this prior proposal tobacco'wast, which could otherwise not be used, was to be subjected to water extraction and the extract used for improving the flavor of tobaccos for ever, to be pursued in accordance with the method of the U.S.

Pat. No. 3,174,485 which proposed that certain organic com- I pounds should be added to avoid variations in flavor in a particular cigarette tobacco mixture. The method was not intended to produce new flavor qualities in a tobacco.

One object of the present invention is to overcome these difficulties occurring with prior art methods.

A further aim of the invention is to enrich the smoke aroma of tobaccos which have a poor aroma.

A further object of the invention is to provide a method of compounding a cigarette tobacco mixture in which, without any impairment of the smoke quality occurring, some expen' sive components are omitted and replaced by chemically prepared substances or by extracts.

' It has been found that tobacco can be given a tangy flavor, spoken of as nutty by some experts, by treatment with a compound of the following general formula This group of substances has such a powerful influence on tobacco smoke that only 0.001 percent by weight is required to provide for a distinct influencing of the smoke flavor. At this concentration a substance of the above general formula, or several such substances applied together do not have any harmful influence on tobacco either from the taste aspect or from the physiological aspect. Owing to their low vapor pressure the substances remain in tobacco during storage for long periods of time without any loss in aroma being noted. Owing to the ease with which they are entrained by steam in tobacco during smoking they are readily carried by the main smoke stream into the mouth of the smoker and no flavoring proper ties are lost.

Substances in accordance with the above general formula can be added singly or in admixture in any convenientmanner to tobacco or part of a tobacco mixtureuFor instance the quantity added can be within the range of 0.00l to L0 percent by weight of the tobacco, the preferred range being 0.0l to 0.1 percent.

Application can for example be by dipping the tobacco in solutions of the substituted pyrrols in suitable highly volatile solvents. Application can also be carried out by spraying on such solutions. The application can be at any suitable stage in the tobacco manufacturing process, for example in the case of cigarette production. it has been found convenient to spray on an 1-5 percent W/V- ethanolic solution of the substance or substances onto cut tobacco before it is passed into a cigarette making machine.

The substances to be used in the method in accordance with the invention can be readily synthesized in accordance with the method of V. R. Skvarchenko (C. A. 45l8d l958)). For example, a-ethylacetoacetic ester can be converted into methylethyl malomitrile as the bisulfite compound using sodium cyanide. From the methylethyl malonitrile methylethyl maleic anhydride can be obtained by saponification and dry distillation. The maleic anhydride can be converted readily into methylethyl maleimide by heating with urea. The steps in the reaction can be shown as follows:

Preparation of substances for use in the method of the invention and as starting materials for the production of such substances is as follows:

l a-ethylacetoacetic ester To a boiling solution of 34.5 g. sodium in l liter absolute ethanol 195 g. acetoacetic ester and g. ethyl bromide were added dropwise. After boiling for 8 hours the sodium bromide was filtered off, the alcohol distilled off and the residue fractionated, at the boiling point range of 82 to 84/ C. The yield is 191 g., approximately 81 percent.

53 g. of a-ethylacetoacetic ester were stirred for 48 hours with a solution of 38 g. sodium bisulfite in 150 ml. water. Following this 20 g. of sodium cyanide were added and stirring was prolonged for a further 3 hours. The upper oily phase were separated and was boiled with twice its volume (100 ml.) of concentrated hydrochloric acid under reflux cooling. After the reaction was terminated the hydrochloric acid was evaporated and the residue subjected to dry distillation. The distillate was dissolved in ether, washed a few times with a little water, dried over sodium sulfate and the ether evaporated. The residue was distilled at 105-1 l/m C. The boiling point was 105-] /1o C. and the yield 49 percent.

Further materials in accordance with the invention can be prepared as follows. They are presented in the following table together with their formulas.

I Maleic anhydride I C4H2O3: M.P. 52.60 (1.; molecular weight 98; B.P. 198 0.; B.P.3 122 0.; U.V.., 208 (3.90), 290 (1.11)

A 210 nm. IR 1770, 1070, 890, 835, 690 emf.

Theoretical composition: C, 49.00; H, 2.06. Found: C, 49.37; H, 2.08.

II 3-methyl-maleic anhydride C H O B.P., 213214C.; molecular weight, 112; UV see I; IR 1760, 1230, 970, 885, 780, 697 0111?.

Theoretical composition: C, 53.58; H, 3.60. Found: C, 53.88; H, 3.56.

III 3-ethyl-maleie anhydride C H O B.P. 104 0.: molecular see I.

Theoretical composition: 0, 57.14; H. 4.80. Found:

weight, 126;

IV 3,4-dimethyl-maleic anhydridc I If C H O B.P., 105 0.; molecular weight, 126; UV see I; IR 1760, 1265, 1130, 915, 880, 720c111.

Theoretical composition: C, 57.14; H, 4.80. Found: C, 57.47; H, 4.76.

T 3-1nethyl-4ethyl-malcic anhydride 4 (VI) 3,4-diethyl-maleic anhydride C H O B.P. 0.; molecular weight, 154; UV see I.

Theoretical composition: C, 62.39; H, 6.54. Found: C, 62.32; H, 6.48.

In order to judge the flavoring of the tobacco smoke by the materials used in the method in accordance with the invention, the tobacco mixture for cigarettes free of any aroma materials such as essential oils, was sprayed with a 2.5 percent V/W solution of the substance in question in ethanol. The tobacco was then held fora week at 20 C. and 67 percent relative humidity and then made into cigarettes. The cigarettes so produced were then tested by a panel of experts so as to make a comparison with untreated tobacco mixture as regards flavor. The quantity of solution applied to the tobacco mixture was so chosen that the cigarettes of treated tobacco contained 0.001 percent by weight (or 0.0l percent in the tobacco smoke condensate) more Z-formylpyrrol (as regards the main smoke stream) than was the case with cigarettes of the same but untreated tobacco mixture for purposes of comparison. The necessary quantity of solvent was empirically determined in preliminary tests. The smoking of the cigarettes for these preliminary tests was carried out in accordance with the VdC Standards (see Beitrage zur Tabakforschung l. page 32 (1961), l page 307 (l962)) in accordance with the draft DlN Standard 10.240.

The results of the examination of the tobacco by the panel of experts are set forth in the following table:

; Quantity, per- Assessment of flavor on material centage by basis of comparison with weight of dry untreated tobacco mixture condensate l. l 0.00l slightly fruity. fresh 2. 0.0l dry fruity character.

tangy freshness 3. ll 0.00l dry, aromatic 4. 0.0! tangy freshness. slightly sweet with the savor of Turkish tobacco: 5. ill 0.00l rcminescent of tannin o. 0.0l pleasant aromatic taste. overall impression more pronounced. slightly of Russian leather 7. IV 0.00! mild and sweet character 8. 0.0l very mild and so".

oriental character 9 V 0.001 slightly reminescent of leather lo. 0.01 overall taste more pronounced with slight Russian leather savor 1 l. Vl 0.001 more intensive flavor characteristic than with the cigarettes used for comparison 12. 0.0l reminescent of wood smoke.

oriental tangy character The embodiments of the invention in which an exclusive property or privilege is claimed are as follows.

I. A method of improving the flavor of tobacco smoke in which less than 1 percent of a flavorant is added to the tobacin which R is hydrogen, methyl or ethyl, and R, is hydrogen, methyl or ethyl.

2. A method-in accordance with claim 1 in which the substance is added in a quantity equal to 0.001 to 1.0 percent of the weight of the tobacco.

3. A method in accordance with claim 1 in which the sub stance is added in a quantity equal to 0.01 to 1.0 percent of the weight of the tobacco 4. A tobacco product having added thereto less than 1 percent of a tobacco flavorant sufficient to improve the flavor of the smoking product, said flavorant consisting essentially of a compound having the general formula: 

2. A method in accordance with claim 1 in which the substance is added in a quantity equal to 0.001 to 1.0 percent of the weight of the tobacco.
 3. A method in accordance with claim 1 in which the substance is added in a quantity equal to 0.01 to 1.0 percent of the weight of the tobacco.
 4. A tobacco product having added thereto less than 1 percent of a tobacco flavorant sufficient to improve the flavor of the smoking product, said flavorant consisting essentially of a compound having the general formula:
 5. The product in accordance with claim 4 wherein the flavorant is maleic anhydride.
 6. The product in accordance with claim 4 wherein the flavorant is 3-methyl-maleic anhydride.
 7. The product in accordance with claim 4 wherein the flavorant is 3-ethyl-maleic anhydride.
 8. The product in accordance with claim 4 wherein the flavorant is 3, 4-dimethyl-maleic anhydride.
 9. The product in accordance with claim 4 wherein the flavorant is 3-methyl-4-ethyl-maleic anhydride.
 10. The product in accordance with claim 4 wherein the flavorant is 3,4-diethyl-maleic anhydride. 